A Certain Attractor Field
by soulcage
Summary: A collection of stories extracted from different times and places is presented to a chosen group. These stories contain the lives of many different individuals with their own struggle. The world's outcome is decided by these stories.
1. World Line Alpha: Prologue

**Disclaimer: I absolutely do not own To Aru Majutsu no Index. The series is created by Kamachi Kazuma-sensei.**

 **Hello! Hello! Welcome to my second fic! In relation to my first one, I guess you call this a side story/alternate universe/rewrite. Many of the characters who will appear here will be from A Certain Unscientific Paradigm, but with a slightly different twist, some might even have a completely different appearance, and some might turn completely evil. Paradigm will still be updated though so no worries!**

 **Also, this fic isn't only about time travelling. There's going to be action, slice-of-life, and a bit of romance. Since this is partly a side story, I plan to focus it a little bit more on the non-canon's and clear out some of the stuff I left out in the previous arcs I've written in Paradigm. Hopefully, I can get ITEM to be more active this time around. But before anything else, your feedback will be much appreciated!**

 **To those who followed and faved my first work, thank you so much! And to those I have letdown, I apologize! A special thanks to MistaSilentKiller, Sargent Carsh, and Luxraye!**

 **Now please read and enjoy!**

* * *

 **World_Line_Alpha: Prologue**

* * *

 _ **World's_Departure**_

A door opened with a tiny creak, but somehow, it echoed inside that room which was whiter than snow. Perhaps it was because the researchers wanted to keep it clean as much as possible in order to prevent any irregularities like dust particles during their experiments.

And because of that, a girl named Tsuyuri Aki went passed that door with moisture all over her body and high school uniform. The cleaning agent machine was very thorough in her cleansing. Although she wished that wasn't the case because putting her necktie, blazer, knee-socks and the rest of her uniform back was such a troublesome errand. But the timid girl did not complain as usual. As an esper and a student of Academy City, she had no choice but to comply with the researchers' requests.

Her small leather shoes made small tapping sounds as she walked on the pure white floor towards the center of the room where a large man sat beside a large machine. The man occasionally flipped through the pages of the clipboard he was holding, in stark fascination.

This scene was playing out in front of her eyes yet again. She had already lost count how many times she did this routine, perhaps a hundred? No, that's not enough, maybe a billion? That sounds about right. Although the number of times it has repeated may seem unbelievable, those who work on the Attractor Field research team had already accepted this as if it were natural. "Time" here was a vague concept constantly being observed upon through scientific means. "Time" here did not simply mean the angles made by the hands of a businessman's wristwatch, but a transcendental fourth variable which exists in the entire universe in general.

Although right now, the newly turned freshman Tsuyuri Aki was not concerned with the entire universe or the vague concept of "Time". As any girl debuting in her first year, this was supposed to be a momentous occasion. She wanted to meet her new classmates and feel the atmosphere of being a high schooler for the first time, especially in such a nice weather such as this. Don't forget that those rowdy boys will be slamming their bodies with one another and making subtle touches with their bare skin—

"A-ahem…" She let out a small cough before she sat on the chair opposite the man, but he didn't seem to notice.

She could have been enjoying her first day of school, but instead she was called only to get cooped up inside this blindingly white research laboratory with her power developer. She sighed.

The man strokes his short beard. A name tag with "Tamaki Ebisuno" written in bold letters was hanging on his white lab coat. He would have looked like an esteemed researcher if not for the orange T-shirt under his coat and covering his big belly. If a third party were to look at those two, they would feel uneasy leaving a young, frail-looking girl alone in the same room as this man.

"Good morning, Tsuyuri-kun…" He said in a low grumble.

Tsuyuri responded by looking up from behind the fringes of her dark hair and nodding.

"I apologize for calling you out here all of a sudden. We needed to present some data at the upcoming conference so we were pressed for time."

"It's no problem, sensei…" She replied almost automatically.

"Now then, I know you have studied this many times before through the curriculum we have given you in order for you to understand what our research team is doing, but I'll have to ask you some questions as a refresher, understood?"

The girl nodded.

"Good." The researcher wrote something on the clipboard with his pen. "First off, what is the Many-World's Theory?"

Tsuyuri gathered her thoughts for a while before replying. "It is a theory which states that there are many and different kinds of universes parallel to our own… It is based on the principle that elementary particles such as an electron can behave both as a wave and particle at the same time…." She spoke about it briefly and recalled the image she invented for reminding her what the theory was all about, a long barcode with the black lines represented as electrons in their wave form while the blank spaces as electrons in particle form, and with each barcode labeled on each world. And the number of combinations those black lines and white spaces could take on that barcode was the number of possible worlds which could exist, possibly infinite.

But what is this so-called "world"?

In the past, Tsuyuri Aki had thought this only meant this round, blue and green planet she lived in, but now, to the recently turned freshman girl who became one of Academy City's Level 3 espers, it was everything, from the sun to the stars and to everything else floating about in space a million light-years away, everything.

And this world she was currently present in had an existing duplicate with a completely different barcode attached, and a subtly different kind of appearance. Perhaps in the other world she was attending the first day of school just as she wanted. Or perhaps in the other world _that certain part_ was slightly bigger than what was with her right now.

She looked down on her uniform and sighed, still underdeveloped as ever.

In any case, those worlds which were like different copies of each other had come about when every single electron in the universe decided they would become a particle or a wave this time around. Although "decided" was not entirely correct. The actual process occurs when the that particle is observed upon and measured by a scientist. That is when the world splits into two, one having the electron behavior as a wave and the other as a particle. Each outcome presented a world and with each world created another outcome, making the number of worlds seemingly infinite.

That tiny observation created that change.

And this is where the underlying principle behind the well known abilities of the students in the city of the most advanced technology lies.

A scientist can observe that particle, but he may not be able to choose what outcome will be reached.

But the same cannot be said for the famous students of Academy City. Yes, there are students who have the power to control and manipulate the outcome each time. These people are known as espers.

"That's correct. And that's where your Déjà vu comes in, Tsuyuri-kun." The researcher known as Professor Tamaki remarked as his gray, monotonous eyes looked up from the clipboard. "Currently, time and space are some of the most elusive concepts science has not been able to fully comprehend… yet. In the entire world, not a single person has been able to fully grasp what these dimensions hold for our universe, not even me…" The man looked downcast for a second and brought his eyes back up with a small glimmer. "But you are here now, Tsuyuri-kun. Thanks to Academy City, an esper has been produced with the ability of observing different periods of time and space. Since you are the only one able to observe these parallel worlds, we have to record data on you as much as we can while the AIM diffusion field is at work during a Déjà vu."

Tsuyuri nodded, trying to look as serious as she could.

"Now then, please take off the Inhibitor around your neck. This space was built using the technology made to create the Inhibitor which prevents your AIM from making contact with other AIM's so we are free of outside interference. The possibility of a 'Checkpoint' interfering with the experiment is zero."

She did as she was told and put the black choker with a small rectangular device attached to it on a nearby container.

And when the researcher confirmed she did so, he pushed a button on the large machine beside his office chair, and the steel-covered machine which looked like a capsule opened up like a cocoon and laid out a narrow bed.

"Please proceed with the usual steps in preparation for a Déjà vu." The researcher gestured to the bed.

The girl breathed in and walked towards the bed before lying down.

Professor Tamaki turned to face her and tapped on the computer attached to the machine. "Brain waves all stable. AIM diffusion field stable. Heart rate, vital organs and all other conditions are all stable. RNG number assigned to this world: 567510. Are you ready, Tsuyuri-kun?"

"Yes, sensei…" The timid Tsuyuri Aki rested her head on the soft bed and closed her eyes. "I'll do my best." Before doing so, she gave one last look at this world she was about to leave, the clean white walls, that annoying orange T-shirt, the green apple lying on a desk next to a family portrait at the far corner of the room, and the door which led to her high school debut.

Her eyes switched back to the family portrait. She had not taken notice of it before, or it had never been there before, but it seemed out of place in this pure white room, including that apple. She couldn't make out who was on the picture, but there looked to be three people in it: a father, a mother and a child. It must have been a happy family portrait.

"Are you fully prepared, Tsuyuri-kun? When you wake up, you will be in a completely different world, although it may look just like this one. Your homeroom teacher may be different, the dorm you live in might be relocated, and you're roommate might become the person you hate the most. Are you prepared to accept these changes?"

"Well…" Tsuyuri opened her eyes slightly. _There is nothing in this world I'm particularly attached to. Everything here is only temporary and will eventually vanish with a small poof._ Although she hoped she got to see what the first day of school was like here. "Yes, I'm prepared to leave."

The man nodded. "Then I shall apply forced anesthesia to begin the Déjà vu sequence. Your mind will feel a little bit hazy."

If a third-party were to hear this, then they will definitely be concerned for the young girl.

But regardless, she nodded and accepted what she was given.

"I wish you a safe journey… for the both of us…"


	2. World Line Lambda: Future

**Chapter 1 -** **World_Line_Lambda: Future**

* * *

 _ **Hopelessness - World_Line_?**_

Are we all finally here? Good. I will now begin.

All of you here in this lecture hall right now have been selected by me based on a certain criteria. Each of you has that special something that is rarely found here in Academy City. If I was mistaken in my selection, and you came here without it, then you will sadly not understand any of the things I will show in this presentation, and I would have failed in my task and everything would have been for nothing.

What was that... ? What is it that makes you qualified?

Well, you will find out soon enough.

These footages I will be showing have been taken through various means. Each and every one is different from the other yet still very much related. As audiences and observers, you are required to watch them attentively and not disturb the person next to you.

And as human beings of this world that is on the verge of collapsing because of a sudden, unforeseeable and mysterious calamity, it is your duty to watch for every single detail and find out clues or connections that may help save our world.

That's right, the human population has been reduced to a half, entire cities have been wiped out, depression and fear continues to cover the earth daily. Certainly some of you has lost someone you love. The battle outside has been a long and hopeless one. Even with our espers and the help from outside, we won't be able to advance at this rate. Even with a world this united, I don't think we would stand a chance against that thing which suddenly appeared from the blackness of the so-called Judgment Day. But still, let's carry on, shall we?

Now then, before the generator dies out again, let us begin with this hopelessness. Please quiet down and don't interrupt while the film is playing. If you want to go to the bathroom now, then it's too late. It's time to begin.

Remember, time devours all~

* * *

 _ **Emphathy**_

I sighed as I read through the periodical report that I had taken out from a folder. I rested my elbow on the thick wood of my desk. It was already late at night, and still I'm stuck here at the office, but I was already used to it.

Something truly troublesome had been assigned to me, and I'm not even sure if it will work out just as I wished it would.

Even among researchers there was something like a tier and status. I was at the highest tier. I had several other senior researchers working under my wing, but I did not do the actual research itself, not for the past 10 years at least. So, you could say that I'm well at the top of the food chain, but that was not the case here at this point in time.

Let me remind you what I mentioned earlier: "Something truly troublesome had been assigned to me..."

Something truly troublesome had been _assigned to me..._

And let me remind you again that I was someone who managed the majority of the hardworking scientists, and fairly high-standing ones at that, all with a couple of research groups of their own to handle. I was the one who attends the regular conference meetings between the top brass and give out orders to those under me based on what the top brass, the ones who I stood shoulder-to-shoulder with, have decided on. It was unheard of for someone to just ignore all the formalities and screenings and just flat out place the project on the platter with nothing less than the detailed requirements, but that was what exactly happened here. You know what that meant?

It meant that there was somebody who was even above the food chain who bypass the norm.

Now, it wasn't like I was getting too full of myself after reaching the top and claiming a wife and raising a rowdy son, that I didn't know that there was still somebody who possessed even greater power than me, but after spending the past several years in perfect peace, you tend to forget that other side of Academy City. Just reading over that surname again sends shivers down my spine.

Nevertheless, I couldn't decline no matter how much I wanted to. I'm afraid if I don't follow their orders my family will take the brunt of it all. Things like murder disguised as accidental death or suicide, or even getting drugged and abducted, that you see in movies aren't exactly fictional after all. The consequences are too sickening to imagine.

As I flipped over to the next page to see the actual progress of that troublesome assignment, I began to re-imagine my beautiful wife coming to greet me at our doorstep in nothing but an apron. In the world where my son lived in, I think they called it "moe"? If so, my wife's moe points would be ten times more than that of those 2D girls I see in my son's anime DVD box set! Moe moe waifu, please wait for me until I come home!

"A-ahem..." I cleared my throat as I tried to gravitate back to reality.

The project has finally reached the midway point, but there was still the key element which the theory was surrounded on. We have successfully made the outer shell, but the core is still missing. Now how to go about this will be rather difficult. We still don't know if the theory is plausible or not, we are only certain that if we increase the capability of its mental processing unit, all else like empathy, free will, consciousness, etc., would appear on their own, but it doesn't seem like it would any time soon now that I analyzed the progress we are making. Having consciousness is the bare minimum requirement after all if we were to progress into steps B and C. And so far, we have only done A, which was to create that outer shell, that human body. In truth, that was the easiest step of them all since Academy City's advancement in the field of prosthetic technology was sufficient in creating an entire life-sized human body, although we did some adjustments of our own. Now that the physical realm was done, it was time to focus on the mental realm. It is often debated, but there might also be the third realm, which was the spiritual form or the soul. But we will set that aside for now.

Now then, I knew it was not my place to question the actual purpose of this project, but I had a vague inkling down in my gut that it was not for the sake of the advancement of science, nor was it for any military purpose. Much like a child who was taught to never question his parents' decisions, I was left in the dark. Digging deeper into whatever I could get my hands on, I would go as far as to say that this wasn't related to science at all. I was not going crazy or anything, after all, there were a few of those types of students here in Academy City at the list to consider.

In any case, September was fast approaching, there isn't much time left before the big unveiling so I have to pick up on the pace.

As I was about to reach the end of the page, everything suddenly went dark and voices of annoyances and complaints filled the hallway beyond the door. Another power outage it was.

"Ahhh... Even though this city is so advanced in the technical field, it still hasn't fixed its issue with electricity. Well, this is the unpredictable Academy City after all." I sighed yet again and closed the folder on my papers.

.

The sound of the bell ringing reached our classroom as I lifted my head up from my desk. I wonder how that teacher didn't notice me sleeping in her class. She must have been too focused on her lecture or too eager to leave the classroom than to pay any attention to her students.

Whether that was the case or not, I never found out since by the time my senses regained their peak, everyone was already leaving, including that teacher.

"Well, whatever..." I said to myself as I put my favorite pair of Kotonaru headphones on and left the classroom. Kotonaru was a brand that was gaining popularity recently, but it's not like I was just joining the bandwagon or anything, I have been a fan since the first models reached the shelves. This simple one I was wearing was mostly colored in red, with an orange outer ring in the cups. Yeah, this thing symbolized my fighting spirit as the middle person of the class who generally gets along with everybody!

Why make enemies when you can just make all of them your friends? If anyone were to ask what my motto was, that question would probably pop up in just an instant. I like connecting to people and having a peaceful life.

As I was walking across the bright hallway, I noticed the blazing sunlight appearing through the windows. Amidst the crowds of students, sunlight illuminated the outline of a mature-looking girl who would look good wearing a white sundress at summer. She was playing with the strands of her long, black hair, which fell past her shoulders. She was leaning against the wall to a classroom. I immediately noticed her slender legs wrapped in tight, black stockings. Her sailor uniform was neatly worn and there was no sign of any wrinkle anywhere. She looked much like a splendid masterpiece which no other artwork can compare. Just looking at her makes my heart pound faster than normal.

"Hey there, Nakada Yukio," calmly greeted the girl named Kato Harumi.

And I lost it.

"Harumiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii-senpaaaaaaaaaaaaaaiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii!"

"Toh!"

I rushed forward like a maniac and my upperclassman sent a casual hand-chop on my forehead before I could embrace her. That was bad. I looked like a pervert there, but it was worth it since senpai touched my head with her soft hand, even though it was just a hand-chop. I fell to the floor with a satisfied grin on my face and a steaming mark on my forehead.

"You're 2 year's too young to be attacking me like that. I can't have you get any part of me sprained or else I can't do my businesses anymore, you understand?" She let out a calm smile towards me in her triumph.

D-damn! Such charisma!

"Seriously though, what has gotten into you? If you're going to be a ruffian from now on, then I won't get involved with you anymore." Her words seemed to say that she was not all that serious.

The people around looked at us with bemusement, but Harumi-senpai didn't care.

Her cool eyes looked down on me, but...

"Hey, what's with these two?"

"Is that Yukio-kun again?"

"Look, it's Harumi's lackey."

"Th-that girl has a servant?!"

She suddenly looked away after realizing something. I couldn't see it clearly, but it looks like she was avoiding eye contact with all the students around us, so that probably meant she really was unaffected. As expected of the cool beauty senpai-type, whether it was being the center of this sudden romcom routine or having someone suddenly barge in while she was in the middle of changing her clothes, she would play if off like it was nothing.

A bit of red suddenly showed itself on her troubled face. She probably had a cold. Senpai really is unaffected by any of this.

"Harumi-senpai, that hurts..."

"Don't pretend you're hurt so that I would fawn over you."

"Heh heh heh."

"And don't imagine that with that stupid look on your face."

As the middle person of the class who generally gets along with everybody, I, Nakada Yukio, will follow Kato Harumi-Senpai to the ends of the earth.

With the commotion done and with the people dispersing, I began following Harumi-senpai's back out of the school after she suddenly turned around and walked away.

Just like in the hallway, the sunlight dropped down on the wide asphalt leading towards the school gates. Clouds slowly drifted in the sky of the peaceful afternoon. Classes ended early, but you won't see anyone complaining anytime soon.

I cut across the outgoing students while chasing the pale blue skirt of senpai's sailor uniform. Even with all these students, I could still see her thin figure.

As some of the students in my class, specifically Erika-san and Mayoi-san, smiled and waved at me at the school gate, I smiled and waved back, but the girl who would look good in a white sundress at summer suddenly sped up with a gloomy aura around her so I had to part with them. Fu fu fu, senpai must've spotted a guy he had rejected, and so she had to leave the disaster area before things got awkward. As usual, the number of people after Harumi-senpai was numerous, but I won't lose, she is my idol after all. Even if she thinks I'm just a follower to take advantage on, I won't hand her over to anyone! Academy City was a city where the majority were students after all so I have to think that the entire campus, no, the entire city was a battlefield!

The Kotonaru headphones I was wearing suddenly let out a heavy beat as my blood began to boil.

"Senpai, you're really popular."

"Where did that come from?"

I managed to catch up to her, and she replied with an irritated expression on her face. Ahhh, that guy must've really irritated her. I should pay him a visit and tell him to quit bothering senpai, politely of course since I don't want any trouble.

We made our way to a small park with several rounded tables spread out across the bricked ground. Green umbrellas stood above those tables to give them some shade. There were few people around so everything was quiet. There was a crepe stand not too far away from there.

"We're finally out of the noise. You really have a way of gathering people's attentions, Nakada." She sighed and put her hands on her hips.

Alright, it's thinking time. We're alone now, so what should I do? Since I'm a guy I should be the one to get her drinks and food. What are her favorites again? Black coffee and... donuts? That should do. Okay, mission start!

"Hey, Nakada, what flavor do you want? I have a sudden craving for some blueberry, I hope they have it. Oh, I'm paying by the way so don't worry."

As I was making mental calculations at the speed of a supercomputer, Kato Harumi-senpai went over to the crepe stand while checking on her wallet. C-crap, I was too slow!

Now you must be wondering how we were able to reach this point without actually exchanging relevant words. The truth is that I'm merely a follower who likes senpai, and this was our usual routine. No normal boy could easily approach her let alone become her boyfriend, including me, so it is all thanks to luck that I was able to get this far. She was being kind for letting an average high school boy like me hang around with her.

With a small clunk sound, I placed my headphones down on the table, like a soldier laying his trusted gun down in the midst of recuperation, and my bag beside senpai's on the ground.

Academy City was as peaceful as ever. Even more so with this nice weather. We sat opposite each other and ate our snacks under the bright afternoon.

"I hear there's been a suspicious person coming to our school lately. Nobody has got a clue, but it's disturbing my business," Senpai calmly mentioned out of the blue.

"You're still collaborating with different institutes, senpai? You must be rich already with all the money you are making. You've already taken a step in the adult world and have left us all behind."

"How about you, Nakada? Still living the easy life and playing around? You're not very bright so you should at least be serious with your studies. Really, what will happen to you in the future if you keep this up? " Her voice sounded from bored to a bit serious as the topic of my low grades came out.

She was right. Having low grades is nothing to make fun of. Unlike senpai who gets outstanding grades, works at the student council, and helps with various research institutes, I'm just a member of the go-home club. She doesn't have to worry about finding work or going to college, her future is already set. I have to start taking things seriously in order for the future to not be bleak.

"Ah ha ha ha… senpai, you really do care about me!"

"Not to mention you're only a Level 2. That is the lowest level in our school. Our school doesn't accept dead weights. If you don't want to get expelled then you better work hard."

G-gh! It's a direct hit, captain! The ship is sinking! Abort! Abort!

"At any rate, if you ever find that suspicious person, contact me right away so I can report him to the student council. Got it, Nakada?"

The next day, after school, something surprising caught my attention when I opened my shoe locker. I stared at that for a while. I don't know how long. Must've been a minute or two. The reason for this is because that thing was a white envelope lying flat above my shoes.

It was an envelope, right? It was rectangular, thin, made from fine materials, and likely bought from a special stationary store. Huh… this scene looks vaguely familiar. I swear I see these things all the time in shoujo manga.

In any case, I grabbed it and turned it face up.

A heart.

I blinked twice. Huh… no wait, what does this mean? Surely this isn't something like that… what was it? A lo.. love… love letter? Love letters have decorations on them, right? Even if some don't, then surely an envelope which has been stuck with a bright pink heart would mean a love letter. If my conjecture is correct, then surely all these things points to this thing being a love letter.

Love letter. IT'S A LOVE LETTERRR!

I quickly tore it open and read its contents.

To Nakada Yukio-kun,

I have been watching you for a very long time, and I'm afraid I cannot hold back any longer. I feel an intense pain in my heart whenever I am away from you, and yet when I see you, my world is filled with joy. I want to be closer to you, to touch your brown hair, to stare at your deep, black eyes, to be wrapped in your arms. Just looking from afar just isn't enough anymore. I want to set my feelings straight.

Please meet me at the back of Tokiwadai's West Dormitory after school. I will be waiting patiently.

Love, Shokuhou Misaki.

That's what it read.

Ha… ha ha… hahahahahahahahahahaha!

At last, the time has finally come for youth to reach its very peak! Everything has been leading up to this very point. All my hardships and tears weren't for nothing! I, the unpopular high school freshman, Nakada Yukio, a humble lover of music who has never experienced having a girlfriend in his entire life, received a holy letter from a maiden-in-love! As my burning determination raged on, the Kotonaru headphones I was wearing suddenly let out an intense sound of guitar strings being plucked into a fast paced riff.

That is Academy City for you. This city is full of interesting things.

Now, time for the springtime of youth to continue!

.

That was what I thought.

"Senpai! Senpai! Open up!"

I desperately shouted and banged at the door belonging to Kato Harumi-senpai's dorm room. It was the middle of the night. Outside, the lights were on to fight off the darkness.

I was drenched from the rain from top to bottom. The Kotonaru headphones around my neck was likely drenched as well. A small streak of blood flowed from the side of my head. But all of that wasn't important. A girl with bright ginger-colored hair and sky blue eyes hang from my back. She wore an outfit that looked like a straitjacket for an insane asylum. She was likely sound asleep. I could feel the unnatural heaviness weighing at my back. I don't know why, but I just feel like something is off with her. It's hard to describe, but it's as if I was being burdened and held down by a hollow and empty shell rather than flesh and blood. I don't really know what is going on, but something bad is definitely happening in Academy City!

* * *

 **END AN:**

 **Alright! I finally managed to do a chapter on Attractor. I've been wanting to do this for a long time. It's so refreshing to write up something new for a change!**

 **Just to be clear, the first chapter was only a prologue, so think of this chapter as Chapter 1. I should've done that numbering from the very beginning, but I'm clumsy so I'm sorry for that.**

 **Hoping for your feedback!**


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